Pneumatic Suspension Bellows

ABSTRACT

The invention relates to a combined pneumatic bellow ( 14 ) for a pneumatic suspension ( 10 ), wherein an axle-sided area ( 18 ) of pneumatic bellow ( 14 ) comprises, in a base state, a preshaped adapted from  928 ) and said adapted form ( 28 ) is embodied in such a manner that the axle-sided area ( 18 ) can be arranged on a protruding part ( 30 ) of a plunger  914 ) and the axle-sided area ( 18 ) is configured in such a manner that, in the event of the axle-sided area  918 ) moving towards a frame-sided area ( 16 ) of the pneumatic bellow ( 14 ), the axle-sided area ( 18 ) adapts to the adapted form ( 28 ). The invention also relates to a pneumatic suspension, a vehicle axle system wherein the inventive pneumatic bellow is used and to a method for producing said pneumatic bellow.

The present invention relates to a pneumatic bellows for a pneumaticsuspension/spring, a pneumatic suspension/spring, a vehicle axle systemand a method for manufacturing a pneumatic bellows.

Traditionally, an automotive axle of a commercial vehicle has an axlebody that forms an axle unit at one end by means of at least onelongitudinal swinging arm and is therefore movably coupled to thevehicle frame and is supported with respect to the vehicle frame by apneumatic suspension arranged above or behind the area of intersectionof the axle body and the longitudinal swinging arm. The pneumaticsuspension in turn comprises a pneumatic bellows arranged between acover and a base plate, whereby a plunger is arranged on the pneumaticbellows for mechanical coupling between the pneumatic bellows on the onehand and the axle unit on the other hand. The pneumatic bellows isconnected on its axle-sided area to the plunger, with the outsidesurface of the plunger serving as a rolling surface for the pneumaticbellows, thereby ensuring a guided movement of the pneumatic bellowsduring operation in the up-and-down movement of the plunger.

However, such pneumatic suspensions have only limited suitability forcrane and rail freight loading because the pneumatic bellows iscompletely rolled out without any additional holding devices due to theweight of the axle, which is then hanging beneath the vehicle, therebycreating a vacuum with respect to the environment in the pneumaticbellow. When the vehicle is lowered, there is the risk that thepneumatic bellows might collapse inward and/or be tilted and/or collapsetoward the plunger and therefore unable to roll over the plunger, whichcan result in damage.

To overcome this problem, the spring path of the pneumatic suspension incrane and rail freight loading is therefore traditionally limited on thebasis of a tensioning device and/or safety device attached to thevehicle frame and/or a divided plunger is used. Alternatively, thepneumatic suspension may also be designed so that the pneumaticsuspension is detachably connected to the frame. In crane loading of atrailer by means of a readjusting device, the pneumatic suspension isseparated from the frame, and the cover and therefore also thesuspension bellows are held in a defined position with respect to theplunger by means of the readjusting device so that the suspensionbellows will roll over the plunger and/or be held in an unreeled state.

The object of the present invention is to provide a pneumatic suspensionsuitable for crane loading of vehicles in a simple manner.

This object is achieved by the pneumatic bellows according to Claim 1,the pneumatic suspension according to Claim 14, the vehicle axle systemaccording to Claim 16 and the method for manufacturing a pneumaticbellows according to Claim 17. Preferred embodiments are the subject ofthe dependent claims.

According to the present invention, a pneumatic bellows is madeavailable for a pneumatic suspension, whereby

-   -   an axle-sided area of the pneumatic bellows has a preformed        adapted shape in a basic state,    -   the adapted shape is designed so that the axle-sided area can be        arranged on a protrusion on a plunger,    -   the axle-sided area is designed so that with movement of the        axle-sided area toward a frame-sided area of the pneumatic        bellows, the axle-sided area assumes the adapted shape.

The axle-sided area preferably always assumes essentially the adaptedshape with a movement toward the frame-sided area of the pneumaticbellows.

The basic state of the pneumatic bellows in the sense of the presentinvention is a state in which no external outside forces such as tensileforces, thrust and/or shearing forces act on the pneumatic bellows. Inparticular, the basic state of the pneumatic bellows is the state of thepneumatic bellows when the pneumatic bellows installed in a pneumaticsuspension is inflated once by means of compressed air, for example, andthen the compressed air is released from the pneumatic suspension, i.e.,ambient pressure again prevails in the interior of the pneumaticsuspension. In the basic state, no additional force is applied to thepneumatic suspension after inflation, apart from its own weight.

The pneumatic bellows may also have an operating state. The operatingstate is when, for example, the pneumatic suspension is arranged in thetraditional manner, wherein the internal pressure in the pneumaticbellows differs from ambient pressure, for example. This operating stateoccurs, for example, when the vehicle is being used in the traditionalmanner. The operating state may also be a state in which the pneumaticbellows is deflated, e.g., when the device such as a tractor trailer onwhich the pneumatic suspension is parked for a lengthy period of time.In this case, ambient pressure prevails in the interior of the pneumaticbellows as in the basic state, but a force, namely a portion of theweight of the frame, possibly including the load, has been applied atleast briefly. In the operating state of the pneumatic bellows, thelength of the pneumatic suspension is usually less than the length ofthe pneumatic suspension in the basic state of the pneumatic bellows.

In addition, the pneumatic bellows may have a load state, said loadstate occurring when the vehicle is loaded by crane onto a freight car,for example, i.e., the axle unit is suspended from the pneumaticsuspension. In the loading state of the pneumatic bellows, the pneumaticsuspension is usually longer than in the basic state of the pneumaticbellows, as measured along the midline of the suspension.

If the pneumatic suspension is acted upon with a very high internalpressure in the operating state of the pneumatic bellows, it is alsopossible for the pneumatic suspension to have the same dimensions as inthe loading state of the pneumatic bellows.

The pneumatic bellows may also be in its basic state when it isuncoupled from the plunger, for example, i.e., the pneumatic bellows issupported alone, for example.

If a trailer on which a pneumatic suspension is provided is loaded ontoa freight car, a ferry or the like, the pneumatic bellows is essentiallyextended completely due to the weight of the axle when the trailer ishoisted via the chassis, i.e., the frame. When the trailer is set downon the freight car and/or the ferry, the pneumatic bellows is designedin particular to resume the state prevailing prior to hoisting. Thisstate may be the basic state, for example, especially if the pneumaticbellows is collapsed, and/or it may be a state deviating from the basicstate if the pneumatic bellows is acted upon by an internal pressure,for example.

The adapted shape of the axle-side area is preferably designed so thatthe pneumatic bellows always rolls over the plunger in a movement of theaxle-sided area toward the frame-sided area.

In other words, the pneumatic bellows may essentially be extended fullyin hoisting a trailer while it is being loaded onto a freight car and/ora ferry. If the trailer is set down on the freight car and/or the ferry,the pneumatic bellows roll over the plunger although a low internalpressure prevails in the pneumatic bellows. Tilting and/or collapsing ofthe pneumatic bellows is/are prevented by the adapted shape of thepneumatic bellows. In particular the pneumatic bellows again rolls overthe plunger even if the pneumatic bellows has collapsed inward due tothe low internal pressure. Therefore, it is advantageously not necessaryaccording to the present invention to limit the maximal reboundclearance in loading, e.g., on the basis of an arrester cable as thepreferred gripping device and/or tensioning device. In particular, it isalso advantageously not necessary to design the plunger to be divided.Instead, the problems of the state of the art are solved easily with theinventive pneumatic bellows.

The present invention advantageously ensures that due to the shapememory of the axle-sided area of this pneumatic bellows, the pneumaticbellows rolls over an outside circumference of the plunger, i.e., thepneumatic bellows is in contact with an outside circumference of theplunger. Shape memory in the sense of the present invention means thatthe axle-sided area of the pneumatic bellows is always attempting tofirst assume the adapted shape in a movement of the axle-sided area ofthe pneumatic bellows toward the frame-sided area of the pneumaticbellows.

The adapted shape is preferably designed so that after essentiallycomplete extension of the pneumatic bellows in a movement of theaxle-sided area toward the frame-sided area, the axle-sided area willhave the adapted shape.

In other words, the pneumatic bellows may be essentially completelyextended and/or stretched. Owing to the shape memory of the axle-sidedarea of the pneumatic bellows, however, the axle-sided area essentiallyassumes the adapted shape when there is a load on the pneumaticsuspension from the outside, and the pneumatic bellows will roll alongthe plunger even when a relative vacuum prevails in the interior.Tilting and/or unwanted collapse of the pneumatic bellows is thereforeadvantageously prevented.

Due to the essentially complete extension of the pneumatic bellows,i.e., when the pneumatic suspension has essentially reached its greatestpossible length, it is also possible that the adapted shape is no longerpresent on the axle-sided area in the essentially completely extendedstate. However, when the pneumatic suspension is under load, i.e., whenthe length of the pneumatic suspension is reduced, the axle-sided areafirst resumes the adapted shape owing to the shape memory of theaxle-sided area and the pneumatic bellows therefore then rolls over theoutside of the plunger.

The adapted shape is especially preferably designed to extendessentially around one end of the protrusion on the plunger.

The axle-sided area of the pneumatic bellows is therefore essentiallycompletely in contact with the protrusion; the axle-sided area of thepneumatic bellows is in contact with at least a tip and/or an end of theprotrusion and preferably also in contact at least slightly with thesurfaces surrounding the tip and/or end and/or free end area of theprotrusion. In other words, the adapted shape of the axle-sided area ofthe pneumatic bellows is in contact with the inside of the plunger in atleast some areas, preferably surrounding the tip and/or end of theprotrusion, and is also in contact with the outside of the plunger insome areas. The outside of the plunger here is the side of the plungerthat faces away from a longitudinal axis of the plunger, i.e., isessentially in contact with the environment. The inside of the plungeris a side that faces toward the longitudinal axis of the plunger.

If the pneumatic bellows is completely extended in loading, for example,it is possible for the adapted shape to no longer extend around theprotrusion but instead to be arranged only in at least some areas on theinside of the plunger. The axle-sided area of the pneumatic bellows,which has the adapted shape in the basic state, may be spaced a distanceaway from the protrusion on the plunger already before the end and/orthe tip of the protrusion, for example. However, if the frame-sided areaof the pneumatic bellows is forced and/or moved toward the axle-sidedarea of the pneumatic bellows, then because of the shape memory, theadapted shape of the axle-sided area of the pneumatic bellows isre-established again first, and then the axle-sided area essentiallyextends around the protrusion on the plunger according to its adaptedshape. Next, with a further movement of the axle-sided area toward theframe-sided area, the pneumatic bellows rolls along the plunger.

The adapted shape of the axle-sided area of the pneumatic bellowsextends in particular along the inside of the protrusion on the plungeras well as at least partially along the outside of the plunger. Thus, inits adapted shape, the axle-sided area of the pneumatic bellows isadapted to the protrusion on the plunger, with the axle-sided area beingin contact with the inside of the plunger according to the adapted shapeand extending toward the end of the protrusion on the plunger as well asextending toward an axle-sided bearing of the pneumatic suspension onthe outside of the plunger. The axle-sided bearing of the pneumaticsuspension may be positioned differently with different trailers. Theaxle-sided bearing may be a plunger mount or a pneumatic suspensioncarrier. The pneumatic suspension carrier may be arranged on a swingingarm of the axle unit, for example. The axle-sided area of the pneumaticbellows in the sense of the present patent application is the end areaof the pneumatic bellows which is connected to the axle-sided bearing ofthe pneumatic suspension, i.e., the area of the pneumatic suspensionthat is arranged on the plunger, by means of the plunger and optionallyother positioning means. The frame-sided area of the pneumatic bellowsis the area of the pneumatic bellows which is connected to the frame bymeans of a cover and optionally other arranging means.

With this movement of the frame-sided area of the pneumatic bellowstoward the axle-sided area of the pneumatic bellows, the pneumaticbellows rolls toward the axle on the outside circumference of theplunger.

Consequently, the cross section of the pneumatic bellows, expressedmathematically, has a minimum. This minimum occurs on the axle side of amaximum of the adapted shape of the axle-sided area—with a movement ofthe frame-sided area of the pneumatic bellows toward the axle-sided areaof the pneumatic bellows—and the minimum is moved toward the axle withthis movement. Likewise, the protrusion on the plunger has a maximum andthe adapted shape of the axle-sided area of the pneumatic bellows is incontact with the protrusion on the plunger on both the inside andoutside of this maximum.

The axle-sided area is preferably essentially S-shaped in cross section.The S-shaped cross section is formed here from the maximum of theadapted shape and the minimum of the pneumatic bellows.

In addition, the axle-sided area preferably has a greater wall thicknessthan the remaining pneumatic bellows. In particular, the adapted shapehas a greater wall thickness than the remaining pneumatic bellows.

The pneumatic bellows is preferably designed in multiple layers. Theaxle-sided area is especially preferably reinforced with fabric layers,e.g., metal cloth and/or plastic and/or textile fabric layers,preferably at least in the area of the adapted shape, whereby the fabriclayers may also extend beyond the area of the adapted shape. Inparticular, additional fabric layers may also be arranged in the area ofthe adapted shape.

The pneumatic bellows is especially preferably reinforced with fabriclayers and/or reinforcing layers in at least some areas to increase theradial stiffness of the pneumatic bellows. These fabric layers arepreferably arranged in the so-called central area of the pneumaticbellows at a distance from the axle-sided area.

These fabric layers are in particular closed cylinder segments which areembedded in the pneumatic bellows and have a height of approximately 1cm up to the extent of the central area, preferably from approximately 3cm to approximately 8 cm, especially preferably approximately 5 cm.

The pneumatic bellows is preferably made of a restorable material. Thepneumatic bellows is in particular made of a material having shapememory in the axle-sided area, so that the adapted shape is resumedagain after essentially complete extension of the pneumatic bellows andsubsequent compression of the pneumatic bellows.

The pneumatic bellows is especially preferably made of rubber or anelastomer material having comparable material properties.

The axle-sided area especially preferably has an area that is designedso that the pneumatic bellows can be attached to the plunger by aclamping element.

A ring of a metal is preferably incorporated into the axle-sided area.The ring made of metal is in particular incorporated into the pneumaticbellows on the axle-sided end of the pneumatic bellows.

An additional aspect of the present invention comprises a pneumaticsuspension having a plunger and inventive pneumatic bellows.

The plunger of the pneumatic suspension is preferably designed in onepiece.

Another aspect of the present invention comprises an automotive axlesystem having a rigid axle body, at least one inventive pneumaticsuspension being arranged on the axle body.

According to another aspect of the present invention, a method isprovided for manufacturing pneumatic bellows in the following steps:

-   -   prefabricating the pneumatic bellows,    -   shaping the axle-sided area of the pneumatic bellows according        to an adapted shape and    -   final fabrication of the pneumatic bellows.

Preferred embodiments of the present invention are described in greaterdetail below on the basis of the accompanying drawings in which

FIG. 1 shows a schematic sectional view of the pneumatic suspension suchas that known from the state of the art;

FIG. 2 shows a partial area of a schematic sectional view of a pneumaticsuspension in at least some areas according to a preferred embodiment ofthe present invention;

FIG. 3 shows a schematic sectional view of pneumatic bellows in at leastsome areas according to a preferred embodiment of the present invention.

FIG. 1 shows a pneumatic suspension/spring 110 such as that known fromstate of the art. The pneumatic suspension 110 comprises a plunger 112and pneumatic bellows 114. The pneumatic suspension has a frame-sidedsection, i.e., section 116, and an axle-sided section, i.e., area 118with a middle area 117 arranged between the former. This may also bereferred to as a central area. The frame-sided section 116 is closed bya cover 120. The cover 120 may be connected to the frame of a trailer(not shown), for example.

The axle-sided section 118 is connected by a clamping device 122 to theplunger 112. The clamping device 122 is preferably connected, preferablyby screw connection, to the plunger 112 by connecting means 124, inparticular screws and nuts 124. There is in particular an end area 126of the axle-sided area 118 of the pneumatic bellows 114 between theclamping device 122 and the plunger 112, so that the end area 126 of thepneumatic bellows 114 is clamped between the clamping device 122 and theplunger 112. This ensures a tight but releasable connection between thepneumatic bellows 114 and the plunger 112.

The plunger 112 is a traditional plunger such as that used intraditional pneumatic suspensions 110. The pneumatic bellows 114 is alsoa traditional pneumatic bellows such as that used in traditionalpneumatic suspensions 110, whereby the pneumatic bellows 114 may beeasily removed from the plunger 112, e.g., by at least partiallyreleasing the screws and nuts 124 and moving the clamping device 122 adistance away from the plunger 112. Consequently, the end area 126 ofthe pneumatic bellows 114 is no longer clamped between the clampingdevice 122 and the plunger 112 and the one pneumatic bellows 114 may beremoved and replaced by a new pneumatic bellows 114, in particular.

FIG. 2 shows a schematic sectional view of a partial area of a pneumaticsuspension/spring 10, whereby the left half of the pneumatic suspension10 corresponds to a traditional pneumatic suspension and the right halfof the pneumatic suspension 10 is designed according to a preferredembodiment of the present invention. Accordingly, the reference numeralsused on the left half of the pneumatic suspension 10 are identical tothe reference numerals used in FIG. 1.

The right half of the pneumatic suspension 10 comprises a plunger 12 onwhich pneumatic bellows 14 is arranged. Pneumatic bellows 14 has aframe-sided area, i.e., section 16 (shown in FIG. 3) and an axle-sidedarea, i.e., section 18. The frame-sided area 16 of the pneumatic bellows14 is also closed by a cover 20 (shown in FIG. 3) and connected by aclamping device 22 to the plunger 12, whereby the clamping device 22 isconnected to the plunger 12 by connecting means 24, e.g., screws andnuts 24. An end area 26 of the pneumatic bellows 14 is clamped betweenthe clamping device 22 and the plunger 12, thus ensuring a secureconnection of the pneumatic bellows 14 to the plunger 12.

The axle-sided area 18 of the pneumatic bellows 14 also has an adaptedshape 28. The adapted shape 28 of the axle-sided area 18 is designed sothat the axle-sided area 18 is essentially in contact with a protrusion30 on the plunger 12. In other words, the material of the axle-sidedarea 18 of the pneumatic bellows 14 essentially has complete shapememory, i.e., the axle-sided area 18 is manufactured with apredetermined shape, namely the adapted shape 28, whereby the axle-sidedarea 18 may deviate from the adapted shape due to the application ofexternal forces to the pneumatic bellows 14. Because of the shape memoryof the adapted shape 28 of the axle-sided area 18, the axle-sided area18 essentially resumes the adapted shape 28 after the force has beenremoved, i.e., the axle-sided area 18 is again essentially in contactwith the protrusion 30 on the plunger 12.

In addition, FIG. 2 shows a tip 32 of the protrusion 30. If the curverepresenting the surface 34 of the plunger 12 in the sectional view isdescribed mathematically, the tip 32 of the protrusion 30 corresponds toa peak in this curve. The adapted curve 28 of the axle-sided area 18 ispreferably in contact with the plunger at least in an area from astarting point 36 up to the tip 32 of the protrusion 30. As shown inFIG. 2, the adapted shape 28 may also be in contact with the protrusionbeyond the tip 32, i.e., the adapted shape 28 is in contact with thesurface 34 of the plunger starting from the starting point 36 and beyondthe tip 32 of the protrusion 30.

In the state of the pneumatic suspension 10 shown in FIG. 2, thepneumatic bellows 14 is rolled at least partially over the surface 34 ofthe plunger 12. In other words, the surface 38 of the pneumatic bellows14 comes in contact with the surface 34 of the plunger 12 in at leastsome areas. Furthermore, if the section illustrated in FIG. 2 isdescribed mathematically by the surface 38 of the pneumatic bellows 14,then the surface 38 has a minimum 40 in the sectional view. The minimum40 here is on the axle side of the tip 32 of the protrusion 30 of theplunger 12. If a force is applied to the pneumatic bellows 14 along adirection of pull 42, e.g., by moving the frame-sided area 16 of thepneumatic bellows 14 away from the axle-sided area 18 of the pneumaticbellows 14, the pneumatic bellows 14 rolls over the plunger 12 and theminimum 40 moves along the direction of pull 42 from the axle (notshown) of the trailer (not shown) to the frame (not shown). However, ifa force is applied to the pneumatic bellows 14 opposite the direction ofpull 42, e.g., by moving the frame-sided area 16 of the pneumaticbellows 14 toward the axle-sided area 18 of the pneumatic bellows 14,the minimum 40 of the pneumatic bellows 14 moves toward the axle of thetrailer, whereby the pneumatic bellows 14 rolls over the plunger 12.

In loading a trailer having a pneumatic suspension 10 onto a freightcar, for example, a force is applied to the pneumatic bellows 14, e.g.,parallel to the direction of pull 42, and the pneumatic bellows 14 iscompletely extended, i.e., stretched due to the weight of the axle inparticular. Therefore, the pneumatic bellows 14 reaches its maximallength in loading the trailer, whereby the axle is preferably held bythe pneumatic suspension and therefore the pneumatic bellows 14 isstretched essentially completely. In this case the minimum 40 is locatedonly slightly on the axle side of the tip 32 of the protrusion 30.However, the minimum 40 may also be just as far away from the axle ofthe trailer as the tip 32 of the horn 30. In special cases, thepneumatic bellows 14 may no longer have a minimum with an essentiallycomplete extension. Instead, the axle-sided area 18 of the pneumaticbellows 14 develops without a minimum directly into the remaining areaof the pneumatic bellows 14. For example, the axle-sided area 18 mayalso deviate from the adapted shape 28 due to the restoration ability ofthe material of the pneumatic bellows 14 and thus the axle-sided area 18may no longer be in contact with the protrusion 30 on the plunger 12,e.g., in the environment of the tip 32 of the protrusion 30.

On the other hand, it is also possible for the pneumatic bellows 14 notto be stretched uniformly. Consequently, when seen in cross section, oneside of the pneumatic bellows 14 is longer than the other side. Forexample, the axle-sided area 18 of the shorter side of the pneumaticbellows 14 here may have the adapted shape 28 and the axle-sided 18 ofthe other longer side will deviate from the adapted shape.

If the frame of the trailer is again placed on the axle, i.e., theweight of the frame presses the frame-sided area of the pneumaticbellows 14 toward the axle opposite the direction of pull 42, then theaxle-sided area 18 of the pneumatic bellows 14 again first assumes theadapted shape 28. When, in addition, the frame-sided area 16 of thepneumatic bellows 14 again moves toward the axle-sided area 18 (orequivalently the axle-sided area 18 moves toward the frame-sided area16), then the pneumatic bellows 14 roll over the protrusion 30 on theplunger 12 along the surface 34 of the plunger 12. Consequently, theadapted shape 28 of the axle-sided area 18 of the pneumatic bellows 14ensures that the pneumatic bellows 14 will not collapse, but insteadwill roll along the plunger 12.

Loading of a trailer here is easily ensured because even when thepneumatic bellows 14 is essentially completely extended, the pneumaticbellows 14 will still roll over the plunger 12 on compression of thepneumatic suspension 10. In particular, collapse of the axle-sided area18 against the protrusion 30 is prevented and thus rolling of thepneumatic bellows 14 is ensured.

FIG. 3 shows pneumatic bellows 14, 114, whereby the left half shows atraditional embodiment of the pneumatic bellows 114, as in FIG. 2, andthe right half shows a design of the pneumatic bellows 14 according to apreferred embodiment of the present invention.

The frame-sided area 16 of the pneumatic bellows 14 is closed by thecover 20. The axle-sided area 18 of the pneumatic bellows 14 has theadapted shape 28, whereby the adapted shape 28 is designed so that theaxle-sided area 18 of the pneumatic bellows 14 is in contact with theprotrusion 30 in at least some areas (shown in FIG. 2). The pneumaticbellows 14 is also shown in FIG. 3 in a basic position, i.e., the basicstate of pneumatic bellows 14, i.e., no external tensile or restrainingforces, thrust or shearing forces act on the pneumatic bellows 14. Thediagram of the pneumatic bellows 14 in FIG. 3 thus corresponds to theshape assumed by the pneumatic bellows 14 when the pneumatic bellows 14is not connected to the plunger 12, for example. The pneumatic bellows14 then assumes the basic position when it is placed and/or supported ona table top or on the ground, for example.

In addition, a length along an axial direction 44 of the pneumaticbellows 14 in its basic position need not correspond to the maximallength of the pneumatic bellows 14. Instead, the maximal length of thepneumatic bellows 14 may be greater than the length of the pneumaticbellows 14 in its basic position, for example, if the pneumatic bellows14 is stretched along the axial direction 44 in loading, for example,whereby in particular the shape of the axle-sided area 18 in the statemay deviate from the adapted shape 28 and, for example, the shape of theaxle-sided area 18 may be identical to the shape of the axle-sided area118 of a traditional pneumatic bellows 114. This is the case inparticular when a trailer is loaded from the road onto a freight car,for example, and the pneumatic bellows 14 is essentially stretched tothe full extent due to the weight of the axle (not shown). When theloading is finished, i.e., the frame (not shown) presses the frame-sidedarea 16 of the pneumatic bellows 14 toward the axle because of theweight of the frame, the axle-sided area 18 first resumes the adaptedshape 28 before the pneumatic bellows 14 rolls further over theprotrusion 30 along the surface 34 of the plunger 12. This ensures thatthe axle-sided area 18 does not collapse and/or become tilted and thatthe pneumatic bellows 14 will roll over the plunger 12. Thus, accordingto the present invention, a simple means of loading a trailer isachieved without requiring a complex design of the plunger 12, e.g., asa two-part plunger or as a movable plunger.

Additional reinforcement of the pneumatic bellows 14 by introduction offabric layers 29 running over areas of the pneumatic bellows, preferablyradially, are arranged preferably in the central area 17, supporting thedesired rolling behavior, in particular in pneumatic bellows 14 having alarge outside diameter. The fabric layers may also be in the form of oneor more radial outer rings that are spaced a distance apart from oneanother or may also be arranged so they are in direct contact with oneanother. The outside rings may also be formed by inserted reinforcinglayers and/or fabric layers that are arranged in the material of thepneumatic bellows or are applied to the inside or outside surface of thepneumatic bellows material.

However, the reinforcing effect may also be achieved merely through asuitable configuration in the pneumatic bellows material, e.g., in theform of corrugated tubing without necessarily requiring additionalreinforcing layers in these areas. To this extent, the material of thepneumatic bellows and/or its wall thickness in the reinforcing areas maybe retained or even varied in a targeted manner. It would thus beconceivable as a configuration to design areas that are curved towardthe outside and/or toward the inside or have a sinusoidal extent in thecross section of the pneumatic bellows and extend in a ring around thelongitudinal axis of the pneumatic suspension—either contacting oneanother or one developing into the other or spaced a distance apart fromone another. Such reinforcing areas may also additionally have theaforementioned reinforcing layers in or on the pneumatic bellowsmaterial.

LIST OF REFERENCE NUMERALS

-   10 Pneumatic suspension/spring-   12 Plunger-   14 Pneumatic bellows-   16 Frame-sided area-   17 Central area-   18 Axle-sided area-   20 Cover-   22 Clamping device-   24 Connecting means/screws and nuts-   26 End area-   28 Adapted shape-   29 Areas of fabric layers and/or reinforcing area-   30 Protrusion-   32 Tip of the protrusion-   34 Surface of the plunger-   36 Starting point-   38 Surface of the pneumatic bellows-   40 Minimum-   42 Direction of pull-   44 Longitudinal direction of an axle-   110 Pneumatic suspension-   112 Plunger-   114 Pneumatic bellows-   116 Frame-sided area-   117 Central area-   118 Axle-sided area-   120 Cover-   122 Clamping device-   124 Connecting means/screws and nuts-   126 End area

1. A pneumatic bellows for a pneumatic suspension, wherein an axle-sidedarea of the pneumatic bellows has a preshaped adapted shape in its basicstate, the adapted shape is designed so that the axle-sided area isarrangeable on a protrusion of the plunger and the axle-sided area isdesigned such that with a movement of the axle-sided area toward aframe-sided area of the pneumatic bellows, the axle-sided area assumesthe adapted shape.
 2. The pneumatic bellows according to claim 1,wherein the adapted shape of the axle-sided area is designed such thatthe pneumatic bellows rolls over the plunger in a movement of theaxle-sided area toward the frame-sided area.
 3. The pneumatic bellowsaccording to claim 1, wherein the adapted shape is designed so thatafter essentially complete extension of the pneumatic bellows in amovement of the axle-sided area toward the frame-sided area, theaxle-sided area assumes the adapted shape.
 4. The pneumatic bellowsaccording to a claim 1, wherein the adapted shape or bellows is designedso that one end of the protrusion on the plunger extends essentiallyaround one end.
 5. The pneumatic bellows according to claim 1, whereinthe axle-sided area essentially has an S-shaped cross-section.
 6. Thepneumatic bellows according to claim 1, wherein the axle-sided area hasa greater wall thickness than the remaining pneumatic bellows.
 7. Thepneumatic bellows according to claim 1, wherein the pneumatic bellows isdesigned in multiple layers.
 8. The pneumatic bellows according to claim1, wherein axle-sided area is reinforced with tissue layers.
 9. Thepneumatic bellows according to claim 1, wherein the pneumatic bellows isreinforced with fabric layers and/or reinforcing layers in at least someareas that increase the radial stiffness of the pneumatic bellows. 10.The pneumatic bellows according to claim 1, wherein the pneumaticbellows is made of a restorable material.
 11. The pneumatic bellowsaccording to claim 1, wherein the pneumatic bellows is made of rubber.12. The pneumatic bellows according to claim 1, wherein the axle-sidedarea has an area that is designed so that the pneumatic bellows isattachable to the plunger by a clamping element.
 13. The pneumaticbellows according to claim 1, wherein a ring made of a metal isincorporated into the axle-sided area.
 14. The pneumatic suspensionhaving a plunger and a pneumatic bellows according to claim
 1. 15. Thepneumatic suspension according to claim 14, wherein the plunger isdesigned in one piece.
 16. An automotive axle system having a rigid axlebody, wherein at least one pneumatic suspension according to claim 14 isarranged on the axle body.
 17. A method for manufacturing a pneumaticbellows, comprising the steps: prefabricating the pneumatic bellows;shaping the axle-sided area of the pneumatic bellows according to anadapted shape and final fabrication of the pneumatic bellows.